Seadrome



Dec. 13, 1960 E. R. ARMSTRONG SEADROME 7 Sheets-Sheet 1 Filed March 15, 1954 FIG. 3.

w m0 MR m m A R D w W D E ATTORNEYS Dec. 13, 1960 E. R. ARMSTRONG 2,963,868

SEADROME Filed March 15, 1954 7 SheetsSneet 2 INVENTOR. EDWARD R. ARMSTRONG ATTORNEYS 1960 E. R. ARMSTRONG 2,963,868

' SEADROME Filed March 15, 1954 7 Sheets-Sheet 4 INVENTOR.

EDY VARD R. ARMSTRONG m\xx.&

ATTORNEYS Dec. 13, 1960 E. R. ARMSTRONG 2,963,858

SEADROME Filed March 15, 1954 7 SheetsSheet 5 INVENTOR.

EDWARD R. ARMSTRONG 'M. imam ATTORNEYS SEADROME 7 Sheets-Sheet 6 Filed March 15, 1954 INVENTOR.

EDWARD R. ARMSTRONG N QE ATTORNEYS 1960 E. R. ARMSTRONG 2,963,868

SEADROME Filed March 15, 1954 7 Sheets-Sheet '7 INVENTOR.

EDWARD R. ARMSTRONG ATTORNEYS FIG. 8.

United States Patent SEADROME Edward R. Armstrong, Monroeville, N.J., assignor to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Filed Mar. 15, 1954, Ser. No. 416,300

8 Claims. (Cl. 6146.5)

This invention relates to a seadrome and, more particularly, to a self-docking fioating apparatus from which operations such as well drilling operations may be carried out over water.

It is an object of the invention to provide a seadrome which may be moved from place to place over water and which, when positioned in a selected location, for example, where offshore well drilling is to be performed, may be solidly founded on the ocean bottom by selfdocking apparatus in water of depths up to and exceeding eighty feet.

The seadrome includes a plurality of buoyancy tanks framed into a truss structure. A deck is mounted on the 'truss structure and is, for example, adapted to support facilities and equipment necessary for drilling operations such as drilling derrick and rig, living quarters, stor- :age area, power plants, mud and other liquid storage vessels, and etc.

In addition to the buoyancy tanks, foundation columns are provided which are adapted to be jacked downwardly into engagement with the ocean bottom whereupon continued jacking will serve to raise the seadrome structure to a sufficient height above the surface of the water so that the deck thereof is above the level of waves normally encountered except during extreme storm con- .ditions.

It is a further object of the invention to provide a :structure of the type described in which the buoyancy tanks and the foundation columns may be dry-docked -while the seadrome is solidly founded on the ocean bottom by raising the buoyancy tanks and truss structure upwardly on the foundation columns and raising individiually foundation columns above the water level.

It is a further object of the invention to provide a seadrome which includes a slot or opening in the structure thereof extending inwardly from one side thereof. This slot is provided so that when well drilling operations are carried out the well casing, pilings and other :support structure therefor, and the conventional Christvmas tree aflixed to the upper end of the casing may be conveniently erected and are conveniently accessible from the seadrome. Furthermore, the slot permits removal of the seadrome from this permanent structure at :any time.

A drilling derrick will extend upwardly from above the platform over the slot as a fixed part of the sea- :drome. When the drilling has been completed, the well casing, the support structure and the conventional Christmas tree mounted on top of the casing will be left remaining and the seadrome carrying the drilling equipment may then be removed. In its place there may be substituted a second seadrome which is equipped as a pumping and storage station. Such a seadrome would pump and store oil which would be removed therefrom at intervals by sea-going tankers. Such a seadrome similar to the seadrome equipped for drilling could be removed from the well location at any time in the event of threatening extreme storm conditions.

"ice

Summarizing briefly, it is the object of this invention to provide a floating seadrome which is self-docking, which provides for dry-docking of all parts of the structure contained therein and which provides for a selfcontained fixed base for continuous operations at sea.

These and other objects of the invention will become apparent from the following description when read in conjunction with the accompanying drawings, in which:

Figure l is a diagrammatic perspective showing of the entire seadrome structure;

Figure 2 is a diagrammatic vertical axial section through one of the seadrome foundation columns, its associated buoyancy tank and'jacking apparatus and the truss structure adjacent thereto;

Figure 3 is a plan view of a buoyancy tank and the truss structure associated therewith;

Figure 4 is a fragmentary showing of a foundation column and its associated buoyancy tank showing the acking apparatus in greater detail;

Figure 5 is a horizontal section through the jacking apparatus taken on the trace 5-5 of Figure 4;

Figure 6 is a horizontal section through the jacking apparatus taken on the trace 6-6 of Figure 4;

Figure 7 is a diagrammatic showing of electrical and hydraulic control circuits by means of which the jacking apparatus may be operated; and

Figure 8 is a diagrammatic showing of alternative electrical and hydraulic control circuits by means of which the jacking apparatus may be operated.

In Figure 1 there is shown generally at 2 a perspective diagrammatic showing of the complete seadrome structure. The seadrome structure includes an open supportmg truss structure 4 into which buoyancy tanks 8 are framed. While the seadrome is shown as having four buoyancy tanks along each longitudinal side thereof, it will be evident that the number and arrangement of buoyancy tanks may be selected in accordance with the structural proportions of any particular seadrome involved. The buoyancy tanks 8 are of annular form and there is a foundation column 10 extending through each buoyancy tank. A foundation tank 12 is aflixed to the lower end of each foundation column. As will be evident oy viewing the figure, the seadrome truss structure may be supported above the surface of the water by the foundation columns with the foundation tank resting on the ocean bottom.

The seadrome struss structure is provided in one end with a slot 6 which is adapted to be positioned around or above a drilling location. A platform is mounted on the seadrome extending across the slot and is adapted to support a conventional type of drilling derrick. Alternatively, a separate drilling platform may be mounted on pilings or other suitable structure fixed to the bottom of the ocean and the slot 6 positioned around this platform while drilling operations are being conducted.

The structural arrangement of the foundation columns, the buoyancy tanks and the truss structure is shown more clearly in Figures 2 and 3. The annular buoyancy tanks 8 are each divided into an upper tank 14 and a lower tank 16. The outer diameter of the lower tank is greater than the outer diameter of the upper tank, thus providing a step 18 between the upper and lower tanks. An annular plate 15 forms the upper surface of the upper buoyancy tank 14 and an annular plate 17 forms the lower surface of the upper buoyancy tank 14 and the upper surface of the lower buoyancy tank 16.

The truss structure indicated at 4 in Figures 1 and 3 includes longtiudinally extending open truss members 20 and longitudinally extending open truss members 22 which are interrupted by the annular buoyancy tanks. The truss structure also includes transversely extending truss members 24 and transversely extending open truss 3 members 26 which are interrupted by the annular buoyancy tanks. Vertically extending shear webs 34 are positioned within'each upper annular buoyancy'tank 14 on radially opposite sides thereof in plane alignment with the interrupted longitudinally extending truss member 22.

-Similar shear webs 35 are positioned within each upper buoyancy tank on radially opposite sides thereof in plane alignment with the interrupted transversely extending truss 26. The shear webs 34 and 35 are joined to the upper and lower annular members 15 and 17 and are joined to the inner and outer walls of the upper buoyancy tank 14. a

The interrupted ends of the longitudinally extending truss 22'are structurally connected to each upper buoyancy tank 14 by a connection between the lower chord 36 of the truss and the step 18 and by a connection between the upper chord 38 of the truss and the upper annular web 15 of the buoyancy tank 14 in the form of suitable tieplates 28. The interrupted truss 26 is similarly connected to the step 18 and to the web 15 by tie plates 29. A vertically extending member such as that shown at 30 joining the upper and lower chords of each truss at each interrupted end of the truss is connected to the outer wall 32 of the'buoyancy tank 14 and thus to the shear webs 34 or 35 within the buoyancy tank. It will be'evident that this'structure provides ring girders in the form of the buoyancy tanks which serve to transfer load between the ends of each of each of the interrupted trusses. 1 7

The foundation columns '10 are elongated cylindrical members which extend through the annular buoyancy tanks 8 and each has aflixed to its lower end a foundation tank 12 having a diameter considerably greater than that of the columns. Each of the columns 10 includes a cylindrical outer shell, eight longitudinally extending plates 43 positioned within the shell and lying on equally spaced radial planes therein and stifiener plates 45 afiixed to the inner edges of the longitudinal plates 43. The columns are also provided with a plurality of spaced annular plates 47 positioned transversely of the columns and afiixed to the outer walls thereof. Each of the annular plates 47 is provided with a stilfener plate 49 extending perpendicular thereto and attached to the inner edge thereof. Each foundation column is provided with a pump 44 and remotely controlled valve means, not shown, in order that the foundation tank and column may be flooded or pumped out in order to adjust the buoyancy thereof. By these means each column may be made torise or settle in the water as may be desired.

A substantial annular space 46 is provided between each buoyancy tank and its associated foundation column to permit access to the inner wall of the annular buoyancy tank as well as to provide space for the jacking apparatus which will be described.

The truss structure is so designed that the seadrome may be supported in a position above the surface of the Water by the foundation columns. Thus access is provided to the entire surface of each of the buoyancy tanks for maintenance or repair while the seadrome is in a self-docked condition at sea. Furthermore, the structure is so designed that any one foundation column may be raised upwardly within its associated buoyancy tank when the seadrome is in a self-docked condition and thus each'foundation column and its foundation tank may be individually dry-docked and thus made accessible at this time.

'Each foundation column is provided with four pairs of spaced flanges 50 extending outwardly and longitudinally of the column and spaced thereon at ninety degree intervals around the column. The pairs of flanges each have aligning recesses 51 adjacent to their outer edges and provide racks for engagement by .a column'jacking assembly.

Each column is provided with four jacking assemblies, one cooperating with each of the four racks mounted on the column. Each jacking assembly includes a double acting hydraulic cylinder 52 having a piston rod 54 extending downwardly therefrom pivoted at its lower end at 55 to a bracket 56 mounted to the top of the buoyancy tank. Each cylinder 52 is provided at its upper end with a transversely extending'pin'58'adapted to fit the recesses 51 of one of the racks 50. A second double acting hydraulic cylinder 60is positioned below the cylinder 52 and has a cylinder rod 62 extending downwardly therefrom and pivoted at its lower end at 63 to a suitable bracket 64 mounted on the interior wall of the buoyancy tank. a v

A roller 68 attached to the bracket 56 serves to guide the foundation column adjacent to the upper end of the buoyancy tank 8. A pair of rollers 70 mounted on a bracket 72 serves to guide the foundation column adjacent to the lower end of the buoyancy tank. Similar upper andlower rollers are provided for engagement with the foundation columns in the region of each of the 'four sets of racks on each of the columns. An additional set of similar upper and lower rollers is provided for engagement with the foundation columns in the regions between the sets of racks. The upper rollers of these sets are indicated at 69 in Figure 3 and are supported by brackets 71. Similar roller and bracket arrangements are positioned below the rollers 69. Each of the brackets supporting the rollers 69, 68 and 70 is provided with a pad 73 forming an extended surface which is adapted to engage the foundation column in the event of the failure of any of the rollers. The pads 73 are positioned relatively close to a foundation column in order to minimize any motion of the column which would occur in the event of failure of a roller.

An arm 74 is rigidly connected to the lower end of the piston rod 54. A hydraulic cylinder 76 is mounted in a frame 78 supported from the top of the buoyancy tank and has a piston rod 80 pivotally connected at its lower end to the arm 74. The cylinder 76 is so arranged that admission of fluid under pressure to within the cylinder acts against, a piston therein and serves to drive the piston rod 80 downwardly and arm 74 in a clockwise direction around the pivot 55. A spring 82 connected between the arm 74 and the frame 78 urges the arm 74 upwardly.

When there is no fluid underpressure within the cylinder 76, the spring 82 will urge the arm 74 upwardly and, when the pin 58 at the upper end of the cylinder 52 engages a recess 51 in the rack 50, a contact 84 mounted on the free end of the arm 74 engages a fixed contact 86 supported by the frame 78. When fluid pressure is admitted to the cylinder 76 moving the arm 74 downwardly against the urging of spring 82, the pin 58 will be carried out of the recess in the rack 50 and the upper end of the cylinderwill be moved in a position disengaged from the rack 50. At this time a contact 88 on the free end of the arm 74 will be in engagement with a contact 90 supported by the frame 78.

A vertically extending rod 92 has its lower end affixed to the arm 74 and its upper end passing through a bore in a member 94 aflixed to the cylinder 52. An upper contact 96 which is mounted on the rod 92 is adapted to engage a contact 98 mounted on the member 94 when the piston rod 54 is extended from the cylinder 52. When the p-istonrod 54 is in a withdrawn position, a contact 100 on the rod 92 will be in engagementwith a contact 102 mounted on the member 94.

A horizontally disposed pair of cylinders 106 have piston rods acting thrcugh a cross bar 108 on a rod which is connected to the upper end of thecylinder 60 through a link 112.

A spring 107 acting between a collar 109 aflixed to the shaft 110 by the cross pin 108 and a fixed guide member 111 urges the rod 110 and the cylinder 60 in the direction of the rack 50. The admission of fluid under pressure into the cylinders 106 serves to draw'the upper end ofthe cylinder 60 out of engagement with the rack 50 and to compress the spring 107.

A contact arm 116 is fixed to the link 112 and, when the cylinder 60 and its piston rod 62 are in extended relation, the upper end of the contact bar 116 engages a contact 118 mounted on a bar 120 affixed to the shaft 110. When the cylinder 60 and its piston rod 62 are in contracted relation, the lower end of the contact bar 116 engages a contact 122. mounted on the lower end of the bar 120.

When the cylinder 60 is withdrawn from engagement with rack 58 by the action of the cylinders 106, the upper end of the bar 120 engages contact 124 supported by the frame 78. When, in response to urging ofthe spring 107, the pin 66 of the cylinders 60 is pisitioned in one of the recesses 51 in the rack 50, the upper end of the bar 120 is in engagement with a contact 126 supported by the frame 78. A mechanism such as that described for moving the upper ends of the cylinders 52 and 60 into and out of engagement with their associated rack bars 50 and the contacts associated therewith is provided with each of the pairs of cylinders associated with each of the four sets of rack bars provided on each of the foundation columns.

In the processes of jacking, i.e., raising or lowering the foundation columns with respect to the buoyancy tanks, the cylinders 52 are referred to as the lifting cylinders and actually serve to raise or lower the column. The cylinders 60 are referred to as holding cylinders and serve primarily to hold the column while the lifting cylinders are being extended or retracted in a position disengaged from the rack. The cylinders 76 and 106 are referred to as retraction cylinders and serve to retract the cylinders 52 and 60, respectively, from engagement with the racks. The jacking control system, as will be described. is designed to provide for engagement of both sets of jacking cylinders with the rack when the system is at rest. The structure previously described provides for engagement of the jacking cylinders with the racks when the pressure in the disengaging cylinders 76 and 106 is relieved. Thus in the event of power failure, the cylinders will be held in engagement with the racks and the foundation columns can move only to the upward or downward limit of the stroke of the holding cylinders.

In Figure 7 there is shown in diagrammatic form the hydraulic and electrical control systems for operating the four pairs of cylinders associated with a foundation column. The hydraulic and electrical connections to each of the four jacking assemblies of each column are identical. The corresponding cylinders of each of the four jacking assemblies of a column are connected in parallel relation and the corresponding electrical contacts of each of the jacking assemblies are connected in series relation. Therefore, in the interest of space and simplicity, Figure 7 shows a first of the four jacking assemblies and a last of the four jacking assemblies with the two intermediate jacking assemblies omitted.

In the drawing, two of the four lifting cylinders are shown schematically at 52 and 52'. The other two lifting cylinders are omitted. Two of the four retraction cylinders 76 for moving the lifting cylinders into and out of engagement with the racks are shown schematically at 76 and 76' with their return springs 82 and 82'. Two of the four holding cylinders are shown schematically at 60 and 60'. Two of the four retraction cylinders for moving the holding cylinders into and out of engagement with the racks are shown schematically at 106 and 106' with their return springs 107 and 107. It is noted that, while the structural arrangement of the retraction cylinders and their springs shown in Figure 7 is conveniently shown not precisely the same as that shown in the structural diagram of Figure 4, the functional relations of the elements in Figure 4 are maintained in the diagram of Figure 7. Thus when hydraulic fluid under pressure is admitted to the retraction cylinders, their associated 8 lifting or holding cylinders are drawn out of engage= ment with the racks and, when hydraulic fluid is discharged from the retraction cylinders, their associated springs serve to urge their associated lifting or holding cylinders into engagement with the racks.

A pump has its inlet end connected to a suitable hydraulic reservoir 132 and pressure is maintained in the output line 134 by means of a conventional pressure relief bypass valve 136. Four solenoid operated hydraulic control valves 138, 140, 142, and 144 are connected to the supply line 134. Each of the control valves is also connected through a return line 154 to'the reservoir 132. The control valve 138 and 142 are fourway valves and each has connected in its return line a hydraulic throttling valve 146 and 150 respectively. The control valves 140 and 144 are three-Way valves and each has connected in its supply line a hydraulic throttling valve 148 and 152 respectively.

Hydraulic lines 156 and 158 are connected to the hydraulic control valve 138. The lifting jack cylinder 52 is connected to the lines 156 and 158 by lines 160 and 162 respectively. The other three lifting cylinders are similarly connected and the four lifting cylinders are thus in parallel relation in the hydraulic circuit. Hydraulic line 164 is connected to the control valve 140. The retraction cylinder 76 is connected to the line 164 by line 166. The other three retraction cylinders 76 are similarly connected to the line 164. Thus all four of these retraction cylinders are in parallel relation in the hydraulic circuit. Hydraulic lines 168 and 170 are connected to the control valve 142. The holding cylinder 60 is connected to the lines 168 and 170 by lines 172 and 174 respectively. The other three holding cylinders are similarly connected to the lines 168 and 170. Thus all four of the lifting cylinders are in parallel relation in the hydraulic circuit. Hydraulic line 176 is connected to the hydraulic control valve 144. The retraction cylinder 106 is connected to the hydraulic line 176 by means of line 178. The other three pairs of retraction cylinders 106 are similarly connected to the line 176. Thus all four of these retraction cylinders are in parallel relation in the hydraulic circuit.

The electrical system includes a pair of conductors 182 and 184 which are connected to a suitable source of power through a conventional disconnect switch 180. Each of the four solenoid controlled hydraulic valves is provided with a pair of solenoid coils. These coils are shown at 188, 190, 192, 194, 196, 198, 200 and 202. One side of each of the coils is connected to the conductor 184. The other side of each of the coils 188 and 190 is connected to one of the terminals of the movable arms of a double pole reversing switch indicated at 204. One of the fixed terminals of the reversing switch is connected to one side of a contact 206 and the other fixed terminal of the reversing switch is connected to one side of a contact 208. The contact 206 is operated by a solenoid coil 210 and the contact 208 is operated by a solenoid coil 212. The two contacts are provided with an interlock arrangement indicated at 214 in order to insure the closure of only one contact at a time. The other side of each of the contacts 206 and 208 and one side of each of the solenoid coils 210 and 212 are connected through a conductor 216 to the conductor 182. It will be evident that energization of the solenoid coils 210 or 212 will control the actuation of the coils 188 or 190 and thus control the position of the valve mechanism within the valve 138. The position of the valve 138 will, of course, determine whether hydraulic fluid under pressure delivered to the cylinders 52 will be in the direction to expand or contract the cylinders.

As previously noted, one side of the solenoid coil 210 is connected to the power line 182. The opposite side of the solenoid coil 210 is connected through a conductor 219 and a series arrangement of contact 218 and identical contacts of each of the four jacking assemblies and amass theconductor 182 and the other side connected to the conductor 184 through a conductor 221 and a series arrangement of the contact 220 and identical contacts of izcgh of the fourjacking assemblies and the conductor One side of each of the coils 192 and 194 of the valve 140 is connected to the conductor 184. The other side of each of the coils is connected to one of the terminals of the movable arms of a double pole reversing switch indicated at 224. One of the fixed terminals of the reversing switch is connected to one side of a contact 226 and the other fixed terminal of the reversing switch is connected to one side of a contact 228. The contact 226 is controlled by a solenoid coil 230 and the contact 228 is controlled by a solenoid coil 232. An interlock arrangement indicated at 234 is provided to prevent both of the contacts 226 and 228 from being closed at the same time. The other side of each of the contacts 226 and 228 and one side of each of the coils 230 and 232 are connected through a conductor 236 to the conductor 182. It will be evident that energization of the coils 230 and 232 will control the position of the valve 140 and thus control the delivery of fluid under pressure to the cylinders 76. 7

As previously noted, one side of the coil 230 is connected to the conductor 182. The other side of the coil is connected through a conductor 241 and a series arrangement of contact 240 and identical contacts on each of the other three jacking assemblies through the conductor 186m the conductor 184. The coil 232 is similarly arranged with one side connected to the conductor 182 and the other side connected to the conductor 184 through a conductor 243 and a series arrangement of contact 242 and identical contacts on each of the other three jacking assemblies and the conductor 186.

The primary side of a transformer 244 is connected through conductors 246, 248 to conductors 184 and 182, respectively. One side of the secondary or low voltage side of the transformer 244 is connected to a conductor 250. The other side of the secondary is connected to ground at 252. One side of a solenoid coil 254 is connected to the conductor 250 through a conductor 251. The other side of the solenoid coil 254 is connected to the contact point 90. The solenoid 254 controls the position of the contact 218. When the retraction cylinder 76 is receiving fluid under pressure from the control valve 140 and the lifting cylinder is moved outwardly out of engagement with the rack. 50, the contact 90 will be engaged by the contact on the member 74 which is grounded through the cylinder mounting structure. Closure of this contact will serve to energize the solenoid coil 254 and close the contact 218. One side of a solenoid coil 256 is connected to the conductor 251. The other side of the solenoid coil 256 is connected to the contact 86. When hydraulic fiuid is exhausted from the cylinder 76 and the lifting cylinder 52 is moved into engagement with its associated rack 50, the contact 86 will be engaged by the contact mounted on the member 74 and the sc moid coil 256 will be energized closing the contact 220. Similar solenoids and contact connections are provided with each of the other three retraction cylinders 76.

One side of a solenoid coil 260 is connected to the conductor 250. The other side of the solenoid coil 260 is connected to the contact 96. When the lffting cylinder 52 is in a fully extended condition, the contact 96 will be engaged by the grounded contact mounted on the .pletely contracted, the contact 100 will engage the.

grounded contact mounted on the member 94. Under this condition the solenoid 262 will be energized and the contact 242will 'be closed.- Similar solenoids and contact connections are provided with each of the other three lifting cylinders. 1 One side of each of the coils 196 and 198 of the control valve 142 is connected to the conductor 184. The other side of each of the coils is connected to one of the terminals of the movable arms of a double pole reversing switch indicated at 264. One of the fixed terminals of the reversing switch is connectedto one side of a contact 266 and the other fixed terminal of the reversing switch is connected to one side of a contact 268. The contact 266 is controlled by a solenoid 270 and the contact 268 is controlled by a solenoid 272. An interlock arrangement indicated at 274 is provided to prevent both of the contacts 266 and 268 from being closed at the same time. The other side of each of the contacts 266 and 268 and one side of the coils 270 and 272 are connected through a conductor 276 to the conductor 1-82. The opposite side of the coil 270 is connected through 'a conductor 277 and a series arrangement of contact 278 and identical contacts on each of the other three jacking assemblies through the conductor 186 to the conductor 184. 7 Similarly, the other side of the solenoid 272 is connected through a conductor 279 and a series arrangement of contact 280 and identical contacts on each of the other three jacking assemblies through the conductor 186 to the conductor 184.

One side of each of the coils 200 and 202 of the control valve 144 is connected to the conductor 184. The other side of each of the coils is connected to one of the terminals of the movable arms of a double pole reversing switch indicated at 282. One of the fixed terminals of the reversing switch is connected to one side of a contact 284 and the other fixed terminal of the reversing switch is connected to one side of a contact 286. A solenoid coil 238 controls the contact 284 and a solenoid coil 290 controls the contact 286. The other side of each of the contacts 284 and 286 and one side of each of the coils 288 and 290 are connected through a conductor 294 to the conductor 182. An interlock arrangement, as indicated at 292, is provided to prevent both of the contacts 294 and 296 from being closed at the same time. The other side of the coil 288 is connected through a conductor 295 and a series arrangement of contact 296 and identical contacts on each of the other three jacking assemblies and the conductor 186 to the conductor 184. The other side of the coil 290 is connected through a conductor 297 and a series arrangement of contact 298 and identical contacts in each of the other three jacking assemblies and the conductor 186 to the conductor 184.

A solenoid coil 302 is connected through a conductor see to the conductor 251. The other side of the solenoid coil 302 is connected to the contact 124. When the cylinder 106 is receiving fluid under pressure from its control valve 144, the holding cylinder 60 is out of engagement with its associated rack 50, and the contact 124 will be in engagement with the member closing the circuit through the coil 302 and closing the contact 278. One side of the solenoid coil 304 is connected to the conductor 300, and the other side of the coil 304 is connected to the contact 126. When the cylinder 106 is not receiving fluid under pressure and the holding cylinder 60 is urged into engagement with a recess in the rack 50 by the spring 107, the contact 126 is in engagement with the member 120 and the solenoid 304 will be energized closing the contact 280. Similar solenoids and contact connections are provided with each of the other three retraction cylinders 106.

One side of a solenoid coil 306 is connected to the conductor 251, and the other side of the coil 306 is con nected to the contact 122. When the holding cylinder 60 is in a contracted position, the contact 122. Will engage the member 116 energizing the coil 306and closing the con-tact 296. A solenoid coil 308 is connected to a conductor 251, and the other side of the coil is connected to the contact 118. When the holding cylinder 60 is in an expanded condition, the contact 118 will engage the member 116 closing the circuit through the coil 308 and closing the contact 298. Similar solenoids and contact connections are provided with each of the other three holding cylinders.

As will be noted from Figure 4, the length of the stroke of the lifting cylinders is slightly greater than the spaces between the recesses 51 in the racks 50. The length of the stroke of the holding cylinders is considerably less than the spaces between the recesses 51 in the racks 50.

The reversing switches 204 and 224 are operated by a common interlock control as indicated by the construction line 203. The reversing switches 264 and 282 are operated by a common interlock control as indicated by the construction line 205.

When the seadrome is afloat and is being moved to a drilling location, the foundation columns 10 and foundation tanks 12 will preferably be pumped dry by means of the pumps 44 and will thus be in their most buoyant condition with their foundation columns positioned with the foundation tanks 12 adjacent to the buoyancy tanks 8 and the greater portion of the foundation columns extending upwardly above the seadrome platform. When the seadrome is positioned in a drilling location, the procedure for docking preferably involves first reducing the buoyancy of the fundation columns until the foundation tanks settle to positions adjacent to the ocean bottom, for example, approximately ten feet from the ocean bottom. From this position the jacking system is put into operation to move the columns downwardly with respect to the seadrome platform and, as the columns come to rest on the ocean bottom, to raise the seadrome platform with respect to the columns. This jacking operation may be referred to as the raising cycle and is accomplished in the manner as will now be described.

The reversing switches 204 and 224 and the reversing switches 264 and 282 will both be closed to the right as viewed in Figure 7. With the reversing switches in these positions and with the hydraulic pump 130 in operation and the master control switch 180 closed, each of the lifting and holding cylinders will proceed through a cycle of operation in which the cylinders expand while disengaged from their associated racks and contract while engaged by their associated racks, thus serving to move the columns downwardly against their buoyancy until they engage the ocean bottom and thereafter to raise the seadrome platform on the columns.

The delivery of fluid to the lifting cylinders is control ed by the valve 138 which is, in turn, controlled by the solenoids 254 and 256 associated with each of the cylinders 76 and acting through the solenoids 210 and 212 and the reversing switch 204. When the reversing switch 204 is closed in the right-hand position, as viewed in Figure 7, and the cylinders 76 are receiving fluid under pressure and the lifting cylinders 52 are all disengaged from their associated racks, the solenoids 254 will be energized, closing the contacts 218, energizing the solenoid 219 which, in turn, energizes the coil 190 of the valve 138 and positions the valve as shown to supply fluid to the lifting cylinders 52 in such a direction as to cause the lifting cylinders to expand. When all of the lifting cylinders 52 are completely expanded and their associated contacts 94 and 96 are closed, the solenoids 260 will be energized, closing the contacts 240 which, in turn, actuate the solenoid 230 and energize the coil 194 of the valve 140 causing the valve 140 to connect the hydraulic line 164 with drain and permits the spring 82 to move the lifting cylinders 52 into engagement with their associated racks.

When the cross pin 58 of each of the lifting jacks 52 position of the valve 138 is changed as a result of energization of the solenoids 256 and 212 and the valve coil k 188 to that in which the lifting cylinders 52 are contracted. This contraction of the lifting cylinders will serve to. depress the foundation columns with respect to the buoyancy tanks and the truss structure.

Upon the completion of the contracting stroke of the lifting cylinders 52, the contact of each of the cylinders is closed with the member 92 associated therewith, the solenoids 262 are energized and the contacts 242 are closed. When each of the contacts 242 are closed, the coil 192 of the valve is energized and the valve. is actuated to supply fluid under pressure to the retraction cylinders 76 to move the lifting cylinders. 52 out of engagement with their associated racks. From the foregoing it will be evident that each of the four lifting cylinders must have completed a step in its operation before any of the four cylinders may proceed with the next step in its operation. Similarly, each of the four retraction cylinders associated with the lifting cylinders can proceed to the next step of its operation only if each of the four lifting cylinders has completed the prior step of its operation. In this manner the four lifting cylinders and their associated retraction cylinders operate. in unison to raise the buoyancy tank with respect to the foundation column.

It will be evident that the lifting cylinder cycle must be repeated sequentially in conjunction with the holding cylinder cycle which will now 'be described. From the foregoing description of the apparatus, it will be evident that the arrangement of the control system for the holding cylinders 60 and their retraction cylinders 106 is substantially the same as the arrangement of the control system for the lifting cylinders 52 and their retraction cylinders 76. The operation of this control system is such that, when the reversing switches 26.4 and 282. are in the right-hand position, as viewed in Figure 7, the holding cylinders 60, when out of engagement with the rack, will receive hydraulic fluid in such a direction as to expand the cylinders and, when in engagement with the rack, will receive hydraulic fluid in such a direction as to contact the cylinders. The operation of the retraction cylinders 106 will be such that, when the holding cylinders have become completely expanded, they will be moved into engagement with the rack and, when the holding cylinders are completely contracted, they will be disengaged from the rack.

It will be noted, however, that the recesses 51 in the racks 50 are undercut and thus, when the cylinders are acting on the recess in the racks, they cannot accidentally become disengaged therefrom. Furthermore, the retraction cylinders 76 and 106 cannot withdraw any of their associated cylinders 52 and 60, respectively, out of engagement with its associated rack until the racks have been moved beyond the limit of the stroke of their associated cylinders. This feature controls the sequential operation of the two sets of lifting and holding cylinders. In other words, when the lifting cylinders have become completely contracted, they cannot be disengaged from the racks until the holding cylinders have been reengaged with the racks and have commenced contracting and have moved the racks a sufficient distance to free, the pins 58 of the lifting cylinders from the recess 51 in which they are engaged. When the holding cylinders have become completely contracted, they cannot be disengaged from the racks until the lifting cylinders have been reenegaged with the racks and have commenced contracting and have moved the racks a sufficient distance to free the pins from the holding cylinders in the recesses in which they are engaged.

When the seadrome has been jacked to a docked condition with the buoyancy tanks and the truss structure supported by the foundation columns, which are at that time solidly founded on the ocean-bottom, operation of the jacking sequence may be arrested and the buoyancy tanks and truss structure held in a stationary position with respect to the foundation colums. Operationof the 11 jacking structure is preferably, but not necessarily, arrested when all of the lifting and holding cylinders are in engagement with recesses in their associated racks. Under these conditions it will be evident that, in the event of any failure in the hydraulic system, relative motion can occur only until one or the other of the sets of cylinders has moved to the end of its stroke.

It will be'evident that the jacking system associated with each of the eight columns will be identical with that described in conjunction with Figure 7. During the jacking operation, while the seadrome is in a partially buoyed condition, the seadrome structure may be maintained substantially level by adjusting the hydraulic operating pressures at 134 as indicated by a gauge 320 on each of the jacking systems of the eight foundation columns. Alternatively, the seadrome may be leveled at any time during a jacking operation by selectively arresting operation of the jacking systems of those columns at which the seadrome has been jacked to an elevation above that of any of the other columns. 7

It will also be evident that any one of numerous well known inclinometers may be employed in conjunction with a control system in order to provide automatic levelling of the seadrome when it is in a docked condition as well as during raising or lowering of the seadrome platform.

After the seadrome has been jacketed to a final docked condition and is leveled therein with the buoyancy tanks and the truss structure supported by the foundation columns, which are at that time solidly founded on the ocean bottom, operation of the jacking systems will be arrested with preferably all of the cylinders in engagement with their associated racks as previously described. If at this time in each of the jacking systems a valve 322 in the line 156 is closed, there will exist in the lifting cylinders a closed off body of oil the pressure in which is responsive to the loading between the buoyancy tank and the foundation column. This loading at each column will be indicated by the pressure reading on a gauge 324 positioned between the valve 322 and the lifting cylinders. It will be evident that the holding cylinders must be positioned intermediate the ends of their strokes in order that all of the loading will be transmitted through the closed off body of oil in the lifting cylinders. Any pressure existing in the oil contained within the holding cylinders will either bleed away of its own accord through the valve 142 or may be reduced to zero by special drain connections not shown in the drawings.

An alternative arrangement may equally well be employed in which a valve and gauge similar to the valve 322 and gauge 324 in the line 156 are positioned in the line 168 of the holding jack system, and the loading transmitted between any buoyancy tank and associated lifting column will then be indicated by the pressure existing in both of these lines. V

It will be evident that either of these arrangements will provide a monitoring system whereby the relative loading of the seadrome structure on the supporting columns may be determined at any time. Inasmuch as a truss structure such as that described supported by foundation columns such as those described is an indeterminate structure with regard to the load distribution therein, it is highly desirable that a load monitoring provision be incorporated in the jacking system. It will further be evident that the gauges 324 in each of the eight jacking systems will serve as load monitoring indicators during a jacking operation aswell as when the seadrome is in a stationary docked condition and. the jacking operation has been completed.

Inasmuch as the jacking system permits jacking of any one column independently of the remaining columns if the foundation tank of any one column should settle. into the ocean bottom to a degree greater than the settlement "of any of the other foundation tanks, the settling will be sass-ass detected by the monitoring system and the column associated withthe settling tank can be jacked downwardly or, more accurately, the portion of the structure surrounding thecolumn can be jacked upwardly in order to level the structure and equalize the loading upon each of the columns.

The lifting cycle previously described is that which is involved when the columns are being lowered with respect to the seadrome platform and the columns are buoyant with respect to the seadrome platform or are supporting the seadrome platform. In other words, the cycle described is involved when the natural tendency of the columns is to move upwardly with regard to the platform.

A reverse condition exists when the columns are being raised with regard to the platform and are in a nonbuoyant condition. This cycleof operation is accomplished by positioning all of the reversing switches 204, 224, 264 and 282 in left-hand positions as viewed in Figure 7. When the reversing switches are in these positions, each of the cylinders will undergo a cycle of operation in which the cylinder expands while in engagement with the column rack and contracts while out of engagement with the column rack. Inasmuch as the column is normally resisting motion in the direction in which it is being jacked,-it is necessary, for example, for the holding jack to engage the rack and raise the column a slight distance in order to free the lifting jack to per mit the lifting jack to be extracted and returned to a contracted condition. It is similarly necessary for the lifting jack to reengage the rack and commence expanding in order to release the holding jack from the rack to permit the holdingjack to be extracted from the rack prior to its contraction stroke.

By proper adjustment of the flow rate control valves 164-452, undesirably rapid rates of operation of the lifting and holding cylinders are prevented when these cylinders are in disengaged conditions. On the other hand, the flow rate control valves are adjusted to permit sufiiciently rapid operation of the disengaged cylinders so as to minimize the period of time during which the cylinders are in a retracted position and thus, during the larger portion of the operating cycle, the pins 58 and 66 of the lifting and holding cylinders, respectively, will be eithter bearing upon the outer surface of the rack or engaged in a recess in the rack.

The system heretofore described for automatically raising and lowering .the foundation columns will not operate under conditions where the column is being raised while it is in a buoyant condition or when the column is being lowered when it is in a non-buoyant condition. By adjustment of the amount of water contained within the column it is possible to avoid the condition of having a buoyant column while it is being raised.

When, however, the column has been raised above the surface of the water in order to dry dock the column and thereafter it becomes necessary to lower the column, the column will, of course, be lowered while it is in a non-buoyant condition. During this relatively brief interval, it is necessary that the column be lowered by manual operation of the jacking system. This can easily be done by operating the hydraulic pump and deenergizing the electrical control system. The valves 138, 140, 142 and 144 are provided with levers 338, 340,- 342, and 344, respectively, by means of which the valves may be manually operated. It will be evident that this manual operation of the jacking system may be employed at any time when manual operation may be desired.

The alternative control system shown by the diagram of Figure 8 is somewhat less complex than that shown in Figure 7 and employs the well known and entirely conventional expedient of substituting, for the exposed contacts shown in Figure 4 such as, for example, the grounded contact 86, an enclosed switch which is adapted 436 and 438 to the jacking cylinders 52.

to be engaged by the moving member 84. In Figure 8 this switch is indicated at 400. Similarly, the contacts 96 and 100 are replaced by limit switches 402 and 404. The contact 126 associated with the holding cylinder 60 is replaced by a switch 406. An additional limit switch 408 is associated with one of the lifting cylinders 52 and is adapted to be actuated by a cam 410 afiixed to the surface of the cylinder, as shown in Figure 8, in a position displaced from the block 102 in order that the cam 410 and its cooperating switch 408 may operate independently of the switch 404 and the block 102 which is affixed to the cylinder 52.

In this system the cylinders 60 are filled with a hydraulic fluid and are connected together. They are not caused to expand and contract during any of the cycles of operation. Thus, for convenience in the following description, the cylinders 60 will be referred to as holding dogs and the cylinders 52 will be referred to as lifting jacks.

A hydraulic pump 412 pumps hydraulic fluid from a reservoir 414 into a supply line 416 at a pressure determined by an adjustable relief valve 418 and indicated on a conventional pressure gauge 420. Three solenoid operated hydraulic control valves 422, 424 and 426 are connected to the supply line 416 and are connected to a return line 428 through throttling valves 430, 432 and 434, respectively. The valve 422 is connected through line The line 436 is connected to the cylinders 52 so as to supply liquid for contracting the jacks, and the line 438 is connected to the cylinders 52 so as to provide liquid for expanding the jacks.

A hydraulic line 440 connected to the valve 424 provides hydraulic fluid to the retraction cylinders 76 to cause the retraction cylinders to pull their associated jacks away from the racks 50. A hydraulic line 442 is connected to the retraction cylinders 106 of the dogs 60 to supply liquid to the retraction cylinders to withdraw the dogs from their racks 50.

The upper portions of the dog cylinders 60 are connected together through a hydraulic line 441. The lower portions of the dog cylinders 60 are connected together through a hydraulic line 443. These cylinders are not supplied with hydraulic fluid except for make-up purposes. The result is that the dogs do not expand or contract but do provide an automatically balanced length adjustment so that, whenever the dogs are in engagement with their associated racks, the loading on the dogs is uniform.

The hydraulic control valve 422 is actuated by a pair of solenoid coils 444 and 446. The hydraulic control valve 424 is actuated by a solenoid coil 448 acting against a return spring 450. The hydraulic control valve 426 is actuated by a solenoid coil 452 acting against a return spring 456.

A pair of conductors 460 and 462 is connected to a suitable source of power through a conventional disconnect switch 458. One side of each of the coils of the hydraulic control valves 422, 424 and 426 is connected to the conductor 460. One side of a coil 464 of a relay 465 is connected to the conductor 460. The other side of the coil 444 of the control valve 422 is connected to one side of a normally open contact 468 of the relay 465. The other side of the coil 446 is connected to one side of a normally closed contact 470 of the relay 465. The other side of the coil 464 is connected to one side of a normally open contact 466 of the relay 465 and is also connected through a conductor 472 and a series arrangement of contacts 402 to the conductor 462. The other side of the contact 466 is connected through a conductor 474 and a parallel arrangement of the contacts 404 to the conductor 462. The other side of each of the contacts 468 and 470 is connected through a conductor 476 to the conductor 462.

As previously noted, one side of the coil 448 is con- 14 nected to the conductor 4652. The other side of the coil 448 is connected through a conductor 478 and a series arrangement of the contacts 406 to a center contact 482 of a reversing switch 480.

As previously noted, one side of the coil 452 is connected to the conductor 460. The other side of the coil 452 is connected through a conductor 484 and a series arrangement of the contacts 400 to the other center contact 486 of the reversing switch 480.

One side of a coil 488 of a relay 490 is connected through a conductor 492 to the conductor 460. The other side of the coil 488 is connected through a. conductor 495 and the contact 408 of one of the lifting jack cylinders 52 to the conductor 462. The relay 490 is provided with a, normally open contact 494 and a normally closed contact 496. One side of each of these contacts is connected through a conductor 498 to the conductor 462. The other side of the contact 494 is connected to a contact 500 of the reversing switch 480 and the other side of the contact 496 is connected to a contact 502 of the reversing switch 480.

The cycle of operation may now be described. Assuming that it is desired to move the column downwardly with respect to the seadrome platform, the reversing switch 480 will be positioned in a down position connecting the contacts 482 and 500 and connecting the contacts 486 and 502, and the master control switch 458 closed. With the remainder of the parts as shown in the drawing, the coil 446 of the hydraulic control valve 442 will be energized, positioning the valve as shown and feeding the blank end of the jack cylinders 52 with oil under pressure and thus moving the cylinders upwardly or expanding the jacks. The contacts 408 are open, the relay coil 488 is deenergized, the contact 494 is open, and hence the coil 448 of the control valve 424 is deenergized. Since the coil 448 is deenergized, the spring 450 will hold the valve 424 in the position shown in which the springs 82 of the jack retraction cylinders 76 will urge the jack cylinder pins 58 against their associated racks 50. The pins 58 will slide along the racks until they reach a slot in the rack at which time they will move in the slot as the result of the urging of the springs 82. When all of the pins are in engagement with a slot in their associated racks, the switches 400 will all be closed, closing the circuit through the coil 452 of the hydraulic control valve 426 and pressure will be applied to the dog cylinders 406 so as to retract the dogs from their associated rack. At this time, however, the pins 66 of the dogs are engaged within the rack recesses and thus the dogs cannot be Withdrawn from the racks.

After the jacks have engaged the recesses in their associated racks 50 and have continued to expand a slight distance therein, the contacts 402 are closed. When all of the contacts 402 are closed, the relay coil 464 is energized and the relay is sealed in through contact 466 and the contacts 404. When the relay coil 464 is energized, the contact 468 closes and the contact 470 opens, resulting in a reversal of the position of the hydraulic control valve 422, causing the jacks 52 to start moving downwardly. Downward movement of the jacks 52 moves the racks 50 downwardly, freeing the pins 66 of the dogs 60 whereupon they are withdrawn from their associated racks by the hydraulic pressure within the retraction cylinders 106. Upon downward movement of the jacks 52, the contacts 402 are opened. This, however, has no efiect on the relay 465 because the relay coil isnow sealed in through the contacts 466 and 404.

The jacks 52 continue their downward movement and, at approximately the midpoint in thisstroke, the switch 408 engages the cam surface 410 and is closed, energizing the coil 488 of the relay 490. Energization of thelcoil 490 serves to close the contact 494 and'open'the' contact 496. Opening the contact 496 deenergizesthe coil 452 of the control valve 426, and permits the spring 456 to position the control valve 426 so as to remove the oil 15 pressure from the retraction cylinders 106, permitting the springs 107 to urge the dog pins 66 into engagement with their associated-racks.

As the jack cylinders 52 approach the bottom of their strokes, the dog pins 66 fall into rack notches in response to the urging of the springs 107. This movement closes the contacts 406 and completes the circuit through the contact 494 of the relay 490 and the coil 448 of the hydraulic control valve 424, actuating the valve 424 to apply hydraulic pressure to the jack retraction cylinders 76 which then act to pull the jack pins 58 out of the recesses in their associated racks. The pins, however, are engaged in the recesses and at this time cannot be removed therefrom. The jack cylinders 52 continue to move downwardly for 'a short distance further and then the block 102 of each of the jack cylinders engages the contact 404, opening the contact and causing the relay coil 464 to be de-energized and causing the position of the control valve 422 to be reversed. The reversal of the control valve 422 causes the jack cylinders to receive hydraulic pressure in such a direction as to expand the jacks whereupon the contacts 404 are then closed. However, the relay coil 464 is not "reenergized due to the fact that the contact 466 thereof is open and the contact 402 is open.

After a short upward movement of the jacks 52 and their associated racks, the lower portion of the notches in the racks engaged by the pins 66 of the dogs come into contact with the pins and take the load of the column and stop its movement. The jacks 52 continue their upward motion until their pins 58 clear the lips of their asso ciated notches in the racks and, at this point, the pins 58 are pulled out of the notches by'the pressure of the fluid in the cylinder 76.

The jack cylinders 52 continue their upward movement and, at about the middle of their strokes, the cam 410 moves clear of the contact 408 and the contact 408 opens, deenergizing the coil 488, opening the contact 494 and closing the contact 496. The opening of contact 494 deenergizes the coil 448 whereupon, in response to the urging of the spring 50, the valve 424 is positioned so as to remove the hydraulic pressure from the cylinders 76 allowing the springs 82 to urge the jack pins 58 into engagement with their associated racks 50. Continued upward movement of the jack cylinders carry the jack cylinders 52 to the position shown in the Figure 8. The jacking system has now completed a cycle and the column has been moved one rack pitch.

It will be evident that, regardless of whether the column is being moved downwardly under a positive load or whether the column is heavy and is attempting to sink of its own accord and being restrained in its downward movement by the operation of the jacking system, the system described in connection with Figure 8 will operate equally well. This is true because of the fact that the system operates to attempt to withdraw the pins 58 of the jacking cylinders from their associated notches before the completion of one stroke of the jacking cylinders and returns the pins into engagement with the faces of the rack prior to the completion of the opposite stroke of the jacking cylinders, and the non-expanding dog cylinders 60 are operated in a similar manner.

When it is desired to raise the columns with respect to theplatform, the reversing switch 480 will be positioned in an up position, closing contacts 500 and 486 and closing contacts 502 and 482, and serving to reverse the control of the relay 490 over the hydraulic control valves 424 and 426. Thus the periods during which the jack retraction cylinders 76 and the dog retraction cylinders 106 are operative will be substantially reversed. Under this condition also it is immaterial whether the columns are buoyant or heavy.

The control system described in conjunction with Figure 8 has several advantages over that described in connection with Figure'7. In the system shown in Figure 8, the

dogs do not extend or contract during raising or lowering operations. They are merely connected together bydraulically so as to equalize the forces all around one column during the holding operation. The result of this is a greatly simplified control system. A further advantage lies in the fact that the lifting jacks never reach the ends of their mechanical strokes and, therefore, the forces on them are balanced at all times around any one column. It is noted that the contacts 400 and 406 form an interlock system which prevents either of the sets of pins 58 and 66 from being withdrawn from their associated rack recesses unless the other set is in engagement with their associated rack recesses.

In the system shown in Figure 8, a pair of gauges 504 and 506 may be positioned to indicate the pressure existing in the hydraulic lines 441 and 443, respectively, interconnecting the dog cylinders 60. These valves will show, when the system is inoperative and also during the jacking cycle, the load carried by each of the columns. Thus the gauges provide a monitoring means whereby the load balance of the entire seadrome may be determined. It will be evident that, if desired, a gauge 508 and 'a shut off valve 510 may be positioned in the hydraulic line 436 to provide for load monitoring of the hydraulic system of the jack cylinders 52, when the system is inoperative, by closing oif the valve 510 and noting the pressure indication on the gauge 508 in conjunction with pressure indications appearing on the gauge 506.

By way of example, it may be set forth that the seadrome structure described herein may be a structure of approximately 220 feet in length, 134 feet in width, and adapted to have a deck level normally approximately 28 feet above the surface of the water. Such a structure would carry the necessary supplies for drilling a 10,000 to 16,000 foot well and provide accommodations for a crew of forty men. The upper and lower portions of the buoyancy tanks and the foundation columns and tanks may be used as storage tanks when the seadrome is in a docked condition.

As previously noted, there is adequate space provided between each of the foundation columns and its associated buoyancy tank to provide access to the inner wall of each annular buoyancy tank for any repairs as may be necessary while the seadrome is at sea. Additionally, any one foundation column may be jacked upwardly while the seadrome is docked and thus individually each of the foundation columns may be dry docked for such repair or service as may be required while the seadrome is at sea.

Each of the foundation tanks 12 are provided with a plurality of jets which are fed through lines 41 and discharge under the conical base 42 of the foundation tank. These jets may be employed to clear and level the ocean bottom before each of the foundation tanks is positioned thereon. Additionally, the jets will serve to break the suction from under a foundation tank when it is desired to raise a foundation column. A still further use for the jets is, by selectively employing jets under each of the foundation tanks when the seadrome is in a floating condition, the seadrome may be propelled at a speed of three to four knots which is suflicient to move the seadrome from the vicinity of drilling operations in the event of an accident or an emergency such as, for example, fire.

It is particularly noted that the open truss structure employed provides a minimum of resistance to the passage of waves through the structure and the construction providing for the framing of the buoyancy tanks into the truss structure wherein the buoyancy tanks provide ring girders for transferring load between the ends of the interrupted trusses and for transferring load between the jacks and the trusses provide a floating structure of limited vertical dimension and a structure which may be raised completely above the water when it is in a docked condition.

The seadrome may also be employed as a fixed storage reservoir supporting means adjacent to a producing well. In this application the seadrome need not provide accommodations for a drilling crew or provision for drilling equipment. A seadrome employed as a storage station would employ the buoyancy tanks, the foundation columns and tanks and additional storage vessels mounted on the seadrome deck to provide storage for oil being produced from a producing well. Tankers would then, at such intervals as would be necessary, pump the oil from the seadrome and carry it away. This structure would eliminate the necessity of laying pipe lines from a produoing well to the shore. It will be evident that such a structure must be capable of withstanding severe weather at sea and thus the open truss structure with the framed in buoyancy tanks and the jacking system described is ideally suited to this type of operation.

What is claimed is:

l. A seadrome including a truss structure comprising crossing transversely and longitudinally extending trusses, means providing a plurality of buoyancy tanks having vertically extending openings passing therethrough and positioned within said truss structure, the tanks interrupting transversely and longitudinally extending trusses and forming ring girders for transferring load between the ends of interrupted trusses, means providing foundation columns extending downwardly through the openings in the tanks, and means for raising and lowering the columns through the tanks mounted on the tanks adjacent to the ends of each interrupted truss, each of the tanks including a vertically extending shear web extending between the inner and outer walls thereof adjacent to the end of each interrupted truss for transferring load between the raising and lowering means and the end of each interrupted truss.

2. A seadrome including a truss structure comprising crossing transversely and longitudinally extending trusses, means providing a plurality of buoyancy tanks having vertically extending openings passing therethrough and positioned within said truss structure, the tanks interrupting transversely and longitudinally extending trusses and forming ring girders for transferring load between the ends of interrupted trusses, means providing foundation columns extending downwardly through the openings in the tanks, means for raising and lowering the columns through the tanks, each of the tanks including a vertically extending shear web extending between the inner and outer walls thereof adjacent to the end of each interrupted truss for transferring load between the ring girder formed by the tank and the ends of each interrupted truss, and guide means mounted on the tanks within the openings therein for guiding the columns extending therethrough, each of said guide means being mounted over a shear web.

3. In a seadrome comprising a structure providing a generally horizontal platform, columns extending downwardly from said platform and adapted to engage the ocean bottom, and means associated with each of said columns for raising or lowering said structure on said columns when said columns are engaging the ocean bottom, raising and lowering means each including a plurality of vertically acting fluid operated jacks, means mounting one end of each jack on the platform and providing for movement of the other end of the jack toward and away from its associated column, receiving means extending longitudinally of said columns adapted to receive said other ends of said jacks, power operated means associated with each jack for selectively moving the jack on its mounting into and out of engagement with its receiving means on the column, and control means for supplying fluid under pressure to said jacks to actuate said jacks and for actuating said jack moving means to selectively either contract said jacks when they are engaged with said receiving means and expand said jacks when they are disengaged from said receiving means, or expand said jacks when they are engaged with said receiving means and contract said jacks when they are disengaged from said receiving means.

4. In a seadrome comprising a structure providing a generally horizontal platform, columns extending downwardly from said platform and adapted to engage the ocean bottom, and means associated with each of said columns for raising and lowering said structure on said columns when said columns are engaging the ocean bottom, raising and lowering means each including a plurality of pairs of vertically acting fluid operated jacks, means mounting one end of each jack of each pair on the platform and providing for movement of the other end of the jack toward and away from its associated column, receiving means extending longitudinally of said columns adapted to receive said other ends of said jacks, power operated means associated with each jack for selectively moving the jack on its mounting into and out of engagement with its receiving means on the column, and control means for supplying fluid under pressure to said jacks to actuate said jacks and for actuating said jack moving means to contract a first jack of each of said pairs of jacks when it is engaged with said receiving means and expand said first jack of each of said pairs of jacks when it is disengaged from said receiving means, and to contract the second jack of each of said pairs of jacks when it is engaged with said receiving means and expand said second jack of each of said pairs of jacks when it is disengaged from said receiving means.

5. In a seadrome comprising a structure providing a generally horizontal platform, columns extending downwardly from said platform and adapted to engage the ocean bottom, and means associated with each of said columns for raising and lowering said structure on said columns when said columns are engaging the ocean bottom, raising and lowering means each including a plurality of pairs of vertically acting fluid operated jacks, means mounting one end of each jack of each pair on the platform and providing for movement of the other end of the jack toward and away from its associated column, receiving means longitudinally of said columns adapted to receive said other ends of said jacks, power operated means associated with each jack for selectively moving the jack on its mounting into and out of engagement with the receiving means on the column, and control means for supplying fluid under pressure to said jacks to actuate said jacks and for actuating said jack moving means to expand a first jack of each of said pairs of jacks when it is engaged with said receiving means and contract said first jack of each of said pairs of jacks when it is disengaged from said receiving means and to expand the second jack of each of said pairs of jacks when it is engaged with said receiving means and contract said second jack of each of said pairs of jacks when it is disengaged from said receiving means.

6. In a seadrome comprising a structure providing a generally horizontal platform, columns extending downwardly from said platform and adapted to engage the ocean bottom, and means associated with each of said columns for lifting said structure on said columns when said columns are engaging the ocean bottom, lifting means each including a plurality of pairs of vertically acting fluid operated jacks, means mounting one end of each jack of each pair on the platform and providing for movement of the other end of the jack toward and away from its associated column, receiving means extending longitudinally of said columns adapted to receive said other ends of said jacks, power operated means associated with each jack for selectively moving the jack on its mounting into and out of engagement with its receiving means on the column, and control means for supplying fluid under pressure to said jacks to actuate said jacks and for actuating said jack moving means to selectively either contract a first jack of each of said pairs of jacks when it is engaged with said receiving means and expand said first jack of each of said pairs of jacks when it is disengaged from said receiving means or expand a first jack of each of said pairs of jacks when it is engaged with said receiving means and contract said first jack of each .of said pairs of jacks when it is disengaged from said receiving means, and to selectively contract "the second jack of each of said pairs of jacks when it is engaged with saidreceiving means and expanded said second jack of each of said pairs of jacks when it is disengaged from said receiving means or expand the second generally horizontal platform, columns extending downwardly from said platform and adapted to engage the ocean bottom, and means associated with each of said columns for lifting said structure on said columns when said columns are engaging the ocean bottom, lifting means each including a plurality of fluid operated jacks,

means pivotally mounting each of said jacks on said platform, means for selectively positioning the jacks on their pivots into and out of engagement with their associated column, and means for holding the column in position with respect to'the platform when its associated jacks are out of engagement with it.

.- 8. .A seadrome including a truss structure comprising crossing transversely and longitudinally extending trusses, a plurality of buoyancy tanks having vertically extending cylindrical openings passing therethrough and positioned within said truss structure, said tanks interrupting transversely and longitudinally extending trusses and forming ring girders for transferring load between the ends of interrupted trusses, each of the tanks including a vertically [extending sheer web extending between the inner and outer walls thereof for transferring load between the end of each interrupted truss and the ring girder formed by the tank, a 'foundation column extending downwardly through the opening in each of said tanks, each of said columns including a cylindrical outer shell, longitudinally extending spaced plates aflixed to the inner wall of the shell and lying radially of the shell, at least some of said column plates .extending in'alignmentwith the interrupted trussesand vertically extending tank sheer webs, and means positioned adjacent to aligning interrupted trusses, tank sheer webs and column plates forlifting said structure on said columns when said columns are engaging the ocean bottom.

References Cited in the file of this patent UNITED STATES PATENTS 103,899 Lewis June 7, 1870 427,149 Brown H May 6, 1890 1,465,664 Griesser Aug. 21, 1923 2,248,051 Armstrong July 8, 1941 2,552,899 Manes May 15, 1951 2,579,703 Rutledge Dec. 25, 1951 2,589,146 Samuelson Mar. 11, 1952 2,600,761 Halliburton June 17, 1952 2,657,540 Templeton Nov. 3, 1953 2,674,857 Fortes Apr. 13, 1954 2,740,261 Stark Apr. 3, 1956 2,771,747 Rechtin Nov. 27, 1956 2,775,869 Pointer June 1, 1957 FOREIGN PATENTS 600,129 Great Britain Apr. 1, 1948 612,201 Great Britain Nov. 19, 1948 515,208 Belgium Oct. 14, 1952 OTHER REFERENCES Engineering News-Record, May 29, 1952, pages 44-45. 

